Disease X is a placeholder: a reminder not to get complacent in our fight against would-be pathogens.
WHO's Research and Development (R&D) Blueprint list tries to distinguish diseases that represent a general health hazard due to their potential for starting a plague and for which there are no, or deficient, countermeasures.
The organization further says, though no individual has been identified as affected by Disease X, man-made deceases are hard to be controlled hence the public should be prepared for worse.
For the purposes of the R&D Blueprint, the WHO developed a special tool for determining which diseases and pathogens to prioritize for research and development in public health emergency contexts.More news: Mourinho unsure about Pogba's availability for Sevilla game
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The R&D Blueprint explicitly seeks to enable R&D preparedness that is relevant for an unknown "Disease X".
John-Arne Rottingen of the Research Council of Norway tells the Telegraph that "history tells us that it is likely the next big outbreak will be something we have not seen before".
Disease X speaks for the information that a genuine global epidemy could be caused by a pathogen, which at present is unknown. "It is vital that we are aware and prepare".
The R&D Blueprint was initially released in 2015, and is reviewed on an annual basis, with the World Health Organization explaining it exists to prioritise the top emerging pathogens likely to cause severe outbreaks in the near future, for which few or no medical countermeasures exist. "It is probably the greatest risk", said Mr Rottingen.
In particular, these experts recognized that existing drugs and vaccines need further improvement for several of the diseases considered but not included in the priority list. This is why is it more probable that new diseases will rise, yet, current travel and trade influence it substantially, so it means that they are even more likely to spread.